Not Applicable
Not Applicable
Not Applicable
This invention relates to a variable mode, turbofan, turbojet, ramjet type jet engine, which is also suitable for short takeoff vertical landing, STOVL. Jet engines are normally built in fixed mode either as turbofans, turbojets or ramjets, this invention sets out to combine all types of engine, plus inclusion of STOVL capability.
According to the present invention there is provided a jet engine comprising of a complete low bypass turbofan unit to the rear, including a secondary fan unit and engine core comprising of compressor, combustion chamber, turbines and secondary bypass duct. Some eight to thirteen feet ahead of which sits a larger diameter main fan unit, driven from the front of the turbofan via a long drive shaft. A center portion of the main fan feeds the secondary fan via a long central duct of roughly the same area as the secondary fan. The outer portion of the airflow from the main fan is ducted into a split exhaust plenum chamber immediately to the rear of the main fan. This chamber has forward mounted thrust-vectoring exhaust nozzles immediately attached to either side, and then each side feeds into variable area outer ducts, using hinged inner and outer doors on either side of the engine. These doors are arranged to split the thrust from the main fan, to exhaust either outwards for bypass or inwards forming a ram into the secondary fan. Both outer ducts then rejoin the long central duct downstream forming a second plenum chamber just ahead of the secondary fan. Between this second chamber and the secondary fan is fitted an in line intercooling device to cool down the incoming air charge.